Thin films

• US 7,419,903 B2
• Filed: 04/13/2005
• Issued: 09/02/2008
• Est. Priority Date: 03/07/2000
• Status: Expired due to Term

• Current Assignee: ASM International NV
• Original Assignee: ASM International NV
• Inventors: Sprey, Hessel, Raaijmakers, Ivo, Kostamo, Juhana, Li, Wei Min, Haukka, Suvi P.
• Primary Examiner(s): Smith; Zandra
• Assistant Examiner(s): Perkins; Pamela E
• Application Number:
  US11/106,220
• Publication Number:
  US 20050181555A1
• Time in Patent Office: 1,238 Days
• Field of Search: None
• US Class Current: 438/627
• CPC Class Codes: C23C 16/029 Graded interfaces
• CPC Class Codes: C23C 16/34 Nitrides C23C16/303 takes precedence
• CPC Class Codes: C23C 16/401 containing silicon
• CPC Class Codes: C23C 16/403 of aluminium, magnesium or beryllium
• CPC Class Codes: C23C 16/405 of refractory metals or yttrium
• CPC Class Codes: C23C 16/452 by activating reactive gas streams before their introduction into the reaction chamber, e.g. by ionisation or addition of reactive species
• CPC Class Codes: C23C 16/45529 specially adapted for making a layer stack of alternating different compositions or gradient compositions
• CPC Class Codes: C23C 16/45531 specially adapted for making ternary or higher compositions
• CPC Class Codes: C23C 16/45534 Use of auxiliary reactants other than used for contributing to the composition of the main film, e.g. catalysts, activators or scavengers
• CPC Class Codes: C30B 25/14 Feed and outlet means for the gases; Modifying the flow of the reactive gases
• CPC Class Codes: H01L 21/0214 the material being a silicon oxynitride, e.g. SiON or SiON:H
• CPC Class Codes: H01L 21/02164 the material being a silicon oxide, e.g. SiO2
• CPC Class Codes: H01L 21/0217 the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz H01L21/02126 and H01L21/0214 take precedence
• CPC Class Codes: H01L 21/02178 the material containing aluminium, e.g. Al2O3
• CPC Class Codes: H01L 21/02189 the material containing zirconium, e.g. ZrO2
• CPC Class Codes: H01L 21/02194 the material containing more than one metal element
• CPC Class Codes: H01L 21/022 the layer being a laminate, i.e. composed of sublayers, e.g. stacks of alternating high-k metal oxides adhesion layers or buffer layers H01L21/02304, H01L21/02362
• CPC Class Codes: H01L 21/02211 the compound being a silane, e.g. disilane, methylsilane or chlorosilane
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/28185 : with a treatment, e.g. annealing, after the formation of the gate insulator and before the formation of the definitive gate conductor
• CPC Class Codes: H01L 21/28194 : by deposition, e.g. evaporation, ALD, CVD, sputtering, laser deposition H01L21/28202 takes precedence
• CPC Class Codes: H01L 21/28202 : in a nitrogen-containing ambient, e.g. nitride deposition, growth, oxynitridation, NH3 nitridation, N2O oxidation, thermal nitridation, RTN, plasma nitridation, RPN
• CPC Class Codes: H01L 21/28562 : Selective deposition
• CPC Class Codes: H01L 21/3141 : Deposition using atomic layer deposition techniques [ALD]
• CPC Class Codes: H01L 21/3145 : formed by deposition from a gas or vapour
• CPC Class Codes: H01L 21/31612 : on a silicon body
• CPC Class Codes: H01L 21/3162 : on a silicon body
• CPC Class Codes: H01L 21/31641 : Deposition of Zirconium oxides, e.g. ZrO2
• CPC Class Codes: H01L 21/3185 : of siliconnitrides
• CPC Class Codes: H01L 21/76846 : Layer combinations
• CPC Class Codes: H01L 21/76873 : for electroplating
• CPC Class Codes: H01L 21/76879 : by selective deposition of conductive material in the vias, e.g. selective C.V.D. on semiconductor material, plating plating on semiconductors in general H01L21/288
• CPC Class Codes: H01L 2221/1089 : Stacks of seed layers
• CPC Class Codes: H01L 29/513 : the variation being perpendicular to the channel plane
• CPC Class Codes: H01L 29/517 : the insulating material comprising a metallic compound, e.g. metal oxide, metal silicate H01L29/518 takes precedence
• CPC Class Codes: H01L 29/518 : the insulating material containing nitrogen, e.g. nitride, oxynitride, nitrogen-doped material

Abstract

Thin films are formed by formed by atomic layer deposition, whereby the composition of the film can be varied from monolayer to monolayer during cycles including alternating pulses of self-limiting chemistries. In the illustrated embodiments, varying amounts of impurity sources are introduced during the cyclical process. A graded gate dielectric is thereby provided, even for extremely thin layers. The gate dielectric as thin as 2 nm can be varied from pure silicon oxide to oxynitride to silicon nitride. Similarly, the gate dielectric can be varied from aluminum oxide to mixtures of aluminum oxide and a higher dielectric material (e.g., ZrO₂) to pure high k material and back to aluminum oxide. In another embodiment, metal nitride (e.g., WN) is first formed as a barrier for lining dual damascene trenches and vias. During the alternating deposition process, copper can be introduced, e.g., in separate pulses, and the copper source pulses can gradually increase in frequency, forming a transition region, until pure copper is formed at the upper surface. Advantageously, graded compositions in these and a variety of other contexts help to avoid such problems as etch rate control, electromigration and non-ohmic electrical contact that can occur at sharp material interfaces. In some embodiments additional seed layers or additional transition layers are provided.

Claims

1. A graded liner layer in a damascene trench comprising:

a first non-graded layer comprising a first compound;

a second non-graded layer, above said first non-graded layer, said second non-graded layer comprising a first metal, wherein between said first and second non-graded layers is a first transition layer comprising both the first compound and the first metal, and wherein the first transition layer has greater than 90% step coverage; and

a third non-graded layer, above said second non-graded layer, comprising a second metal, wherein between the second and third non-graded layers is a second transition layer comprising the first metal and the second metal, wherein the layers are located within a damascene trench.

2. The graded liner layer of claim 1, wherein said second metal is copper.

3. The graded liner layer of claim 2, wherein said first metal is tungsten.

4. The graded liner layer of claim 1, wherein said first compound is selected from the group consisting of:

1) the second metal and nitrogen,

     2) the second metal and nitrogen and carbon,

     3) the second metal and carbon, and

     4) a third metal.

5. The graded liner layer of claim 1, wherein the second transition layer has greater than 90% step coverage, and wherein the second non-graded layer has greater than 90% step coverage.

6. A liner layer comprising:

a first non-graded layer comprising a barrier compound, wherein the first non-graded layer has greater than 90% step coverage;

a second non-graded layer, above said first non-graded layer, said second non-graded layer essentially consisting of tungsten, wherein the second non-graded layer has greater than 90% step coverage; and

a third non-graded layer comprising a seed compound, wherein said third non-graded layer is above said second non-graded layer, and wherein the third non-graded layer has greater than 90% step coverage.

7. The liner layer of claim 6, wherein the first non-graded layer comprises a compound with elements selected from the group consisting of:

tungsten, nitrogen, carbon, and a combination thereof.

8. The liner layer of claim 7, further comprising a first transition layer between the first and second non-graded layers, wherein said first transition layer comprises tungsten and the barrier compound.

9. The liner layer of claim 8, further comprising a second transition layer between the second and third non-graded layers, wherein the second transition layer comprises tungsten and a seed compound.

10. The liner layer of claim 6, further comprising a first transition layer between the second and third non-graded layers, wherein the first transition layer comprises tungsten and a seed compound.

11. The liner layer of claim 6, wherein the seed compound comprises copper.

12. The liner layer of claim 6, wherein the first non-graded layer comprises tungsten, nitrogen, and copper, and wherein the seed compound comprises copper.

13. The liner layer of claim 6, wherein the first non-graded layer comprises tungsten, nitrogen, and copper, and wherein the first transition layer comprises tungsten, nitrogen, and copper.

14. The liner layer of claim 6, wherein the first non-graded layer comprises tungsten, nitrogen, and copper, wherein the first transition layer comprises tungsten, nitrogen, and copper, wherein the second transition layer comprises tungsten and copper, and wherein the seed compound comprises copper.

15. The liner layer of claim 6, wherein the liner layer is on top of a low-k dielectric surface.

16. The liner layer of claim 6, wherein the seed compound consists of copper.

17. The liner layer of claim 6, wherein the first non-graded layer consists essentially of tungsten, nitrogen, and copper.